golang 根据图片url获取图片尺寸

import (
    "github.com/disintegration/imageorient"
    _ "image/gif"
    _ "image/jpeg"
    _ "image/png"
)

func GetImage(url string) (image.Image, error) {
    resp, err := http.Get(url)
    defer resp.Body.Close()
    if err != nil {
        return nil, err
    }
    img, _, err := imageorient.Decode(resp.Body)
    if err != nil {
        return nil, err
    }
    return img, nil
}

im,err := s.dao.Qiniu.GetImage(data["imageUrl"])

　　

im.Bounds().Dx() 和 im.Bounds().Dy() 是我需要的宽和高